Wednesday, October 23, 2013

The best time for your coffee

Ever wonder what the best time is to drink your coffee? You probably know it is not a good idea to drink part of your daily dose of caffeine in the afternoon. Especially for those who have problems sleeping. But, do you ever drink your coffee and feel like it just didn’t work? I know I have that feeling sometimes. The explanation for this has to with a concept that I think is extremely interesting but rarely discussed: chronopharmacology.
coffeeamp.com


Chronopharmacology can be defined as the study of the interaction of biological rhythms and drug action. One of the most important biological rhythms is your circadian clock. This endogenous 24 hour clock alters your physiology and behavior in variety of ways but it can also alter many properties of drugs including drug safety (pharmacovigilance), pharmacokinetics, drug efficacy, and perhaps even drug tolerance. But, what part of the brain produces this 24 hour cycle and what signals does it receive in order for it to do so properly? It has been known for a long time that light is a strong zeitgeber. A zeitgeber is a term used in chronobiology for describing an environmental stimulus that influences biological rhythms. In the case of mammals, light is by far the most powerful. Following the discovery of connections between the retina and hypothalamus (the retinohypothalamic tract), investigations were aimed at the hypothalamus as the putative master clock. Indeed, in some of the most elegant brain lesion experiments, Inouye and Kawamura (1979) provided some of the first evidence demonstrating that the hypothalamus acts as the master clock in controlling the circadian rhythm. By creating an "island" in the brain by methodically cutting the hypothalamus away from any surrounding tissue, the circadian clock was completely lost (Inouye and Kawamura, 1979).

What does that mean? Well, the output of the hypothalamus nucleus (the suprachiasmatic nucleus or SCN) that controls the circadian clock has a variety of functions. The SCN controls your sleep-wake cycle, feeding and energy consumption, sugar homeostasis, and in addition to a few other things it controls your hormones. And, with respect to your alertness, the SCN’s control of cortisol (often referred to as the "stress" hormone) production is extremely important.

Most readers here, especially the ones in science enjoy–and desperately need–their morning coffee. I’ve seen some striking posts (here and here - note the caffeine consumption map with the number of researchers map) on the internet lately showing the correlation between science and caffeine. Not surprisingly to me, wherever there are scientists, there is a lot of caffeine consumed. And, a scientist also happens to be #1 the profession with the greatest caffeine consumption. But, if you are drinking your morning coffee at 8 AM is that really the best time? The circadian rhythm of cortisol production would suggest not.

Drug tolerance is an important subject, especially in the case of caffeine since most of us overuse this drug. Therefore, if we are drinking caffeine at a time when your cortisol concentration in the blood is at its peak, you probably should not be drinking it. This is because cortisol production is strongly related to your level of alertness and it just so happens that cortisol peaks for your 24 hour rhythm between 8 and 9 AM on average (Debono et al., 2009). Therefore, you are drinking caffeine at a time when you are already approaching your maximal level of alertness naturally. One of the key principles of pharmacology is use a drug when it is needed (although I’m sure some scientists might argue that caffeine is always needed). Otherwise, we can develop tolerance to a drug administered at the same dose. In other words, the same cup of morning coffee will become less effective and this is probably why I need a shot of espresso in mine now. Although your cortisol levels peak between 8 and 9 AM, there are a few other times where–on average–blood levels peak again and are between noon to 1 PM, and between 5:30 to 6:30 PM. In the morning then, your coffee will probably be the most effective if you enjoy it between 9:30 AM and 11:30 AM, when your cortisol levels are dropping before the next spike. Originally, when I heard a lecture on this topic, the professor said that since light is the strongest zeitgeber he suggested driving into work without sunglasses on. This would allow for stronger signals to be sent along the retinohypothalamic tract to stimulate the SCN and increase your morning cortisol production at a faster rate. I still tend to drive with them on since I feel blinded by the sun in the morning. However, on mornings when it is partially cloudy out and I did not get a lot of sleep, I drive with them off because this will help me feel more alert than if I was shielding what little sunlight was available. I thought this an important post for anyone but especially with the upcoming Society for Neuroscience annual conference in San Diego. Now us conference attendees should know just when to enjoy their coffee to stay alert for all of the new neuroscience!



References:
Debono M, Ghobadi C, Rostami-Hodjegan A, Huatan H, Campbell MJ, Newell-Price J, Darzy K, Merke DP, Arlt W, & Ross RJ (2009). Modified-release hydrocortisone to provide circadian cortisol profiles. The Journal of clinical endocrinology and metabolism, 94 (5), 1548-54 PMID: 19223520

Inouye, S.T., and Kawamura, H. (1979). Persistence of circadian rhythmicity in a mammalian hypothalamic “island” containing the suprachiasmatic nucleus Proceedings of the National Academy of Sciences of the United States of America DOI: 10.1073/pnas.76.11.5962

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54 comments:

  1. Nice post meh, I learnt something from this post and I'm working on making it useful. The blog reminds me of an equally interesting blog on my reading list http://danieluyi.com Dating and Personal Development Blog .
    keep up the good work.

    Regards

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  2. Love this blog. WISH I'd known for years.. I live in Copehagen and we're losing light fast, especially now that clocks have changed… What's your opinion on Light Lamps???

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    1. Jeneva, just curious if you've looked up something called "Seasonal Affective Disorder"? For whatever reason, scandinavians (and people of scandinavian descent like me) tend to have more trouble with it. We want to go into "hibernation" during the winter.

      Anecdotally, I find my light lamp very helpful when applied shortly after getting up in the morning, while I'm having my morning brew. Though it sounds like maybe I should be delaying my morning brew for a bit!

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    2. Definitely in countries where the amount of light/day and light/season will alter circadian rhythms and while I do not have the reference at hand, in countries with longer nights there does tend to be higher rates of depression/suicide. A lot of major hotels add in 'natural light' light bulbs to help people get over their jet lag faster, which, while this is a good idea, I'm not sure its efficacy has been systematically studied. If you find a reference, let me know! I am going to Japan in a couple months for the second time and that jet lag is really tough to get over.

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    3. Additionally, the circadian rhythm of serotonin and melatonin which are involved in regulating your sleep-wake cycle can be disrupted by inappropriate light exposure. For example, I have often read articles on men's health suggesting that people not read from tablets in bed at night because this will in turn keep you up longer as this is giving the brain cues to stay awake.

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    4. It's good information to know when it is you wake up though. I have irregular sleep patterns. No matter what help it may not be the same for others with different brain chemicals therefor, I have to be one-sided in saying what works for some might not for others.

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  3. Is this timing absolute, or relative to the time a person wakes up? I'm a late riser, myself...

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    1. Nick, I tend to be as well, but I would guess that if you wake up at the same time everyday, and had a full nights sleep, you probably wouldn't need caffeine immediately after you wake.

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    2. But is "between 9:30 AM and 11:30 AM" relative to an assumed wake-up time? If so, what time would that be?

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    3. Nick, yes I believe in this case it is relative to a wake up time that was probably controlled for the study but not specifically mentioned. What they did say was that blood cortisol tends to peak 1 hour after you wake up (with the assumption you are on a regular schedule). Therefore, for their sample in the study, I would assume that they woke up on average at 8 AM. Important for the normal person outside of a controlled study is that, if you are on a routine schedule, you probably don't need to risk 'tolerance' by having caffeine immediately after you wake up since you won't need it.

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    4. Are you kidding? I can't even crawl out of bed without having a cup. Maybe I'm an extreme case, but isn't the while point of coffee to jump start you?

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  4. I understand, and gained a lot. I drink coffee is about ten o'clock to half past ten between.

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    1. Thanks Fornik! I'm glad you found it useful.

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  5. If you are coming to San Diego, best coffee is Zumbar located in Sorrento Valley, close to UCSD.

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    1. Thanks Brian! I think I'll be stuck by the convention center but if I can get out there I will definitely give it a try!

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  6. Hi Steven,
    Found your article really useful. Am in the habit of sipping along a coffee on my way to college, usually around 9. Time to better my routine.

    How can i contact you via email?

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    1. I'm glad you enjoyed it. If you'd like to email me you can here: stevenmiller17@gmail.com

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  7. Why would we want our cortisol levels high? Cortisol has been proven to increase fat accumulation and decrease muscle mass...?

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    1. Cortisol has a lot of functions. I would say it actually gets a bad wrap. That's why I intentionally mentioned its referred to as the 'stress' hormone because it is capable of helping is stressful physiological states but it has a wide-variety of other, normal and important functions. Cortisol, in very large doses can result in fat accumulation (see Cushing's syndrome) and rhabdomyolysis. However, this should not occur in doses that are released as a part of your healthy circadian rhythm.

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  8. putting your sunglasses off with as a result feel more awake in the morning would, regarding to your story, have the same effect as having a cup of coffee.. and therefore be a contradiction, right?

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    1. Great question. It is a contradiction in the sense that yes, they effectively would be doing the same thing but the difference is you won't develop tolerance to light (whereas you would develop tolerance to caffeine if you are taking it when it is not needed) and once your first cortisol peak has occurred, light will no longer help you.

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  9. When I rise, I do two things: Use Visine for my morning dry eyes, and brew my coffee. To keep the tears going, I drop a pinch of crushed red pepper in with the grounds. I need the pepper as much as I need the coffee, now.

    Somewhere on my laptop, I have a simple freeware program that adjusts the color temperature of the screen according to the time of day. The screen has a whiter or blue tint during the day and a reddish tent at night. (I disabled it when another program was causing problems.) It might be useful for those who take their tablets to bed.

    Save your pizza pepper packets for me, OK?

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  10. Interesting post, however I have one concern. This sounds like an entirely reasonable theory about when one should drink coffee. That said, the scientific and medical literature is littered with theories that sounded great but did not turn out to be true, significant, or meaningful.
    What I have read here is enough to justify a hypothesis, but before I believe anything, I would want to see what any clincially-minded person would want: a outcomes-based study. If you want to say that drinking coffee at a certain time improves attention or concentration, you have to actually show that. What I have read here appears to be speculation. Am I missing something or did you just get an article on Digg based on an enducated guess?

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    1. I don't know what Digg is. I used http://www.ncbi.nlm.nih.gov/pubmed for looking for scientific/medical literature (basically the scientific-equivalent to Google with some differences compared to Google Scholar). If you search there you would be able to find many articles when searching with Boolean logic, "caffeine AND cortisol" "caffeine AND shift workers" "caffeine and circadian rhythm," et cetera. Since this blog is generally aimed to be non-technical, I try my best to make this a public information initiative as opposed to a reviews of primary research articles. In terms of outcome measures, again, you should be able to find plenty of these on PubMed if you're interested. There are some striking correlations between the number of major disasters (Chernobyl, 3-mile island, and others) and cortisol levels which again, is associated with attention.

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    2. If the thesis of your article is that coffee should be consumed during a specific window of time in order to positively affect concentration or attention, you should actually link to an article that demonstrates this. You linked to other articles but when it comes to linking to one that supports what you are saying, you tell me to look it up? Saying that this is a "non-technical" blog doesn't really excuse this. As a PhD who is finishing up his MD, I appreciate you communicating science to the community. However if you are extrapolating results and there is no actual study that directly supports your claim, this is highly misleading.

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    3. I came hear after reading an article written by Steven Miller published by Gizmodo titled 'The Scientifically Best Time to Drink Coffee'. I'm looking for your research method, but it appears that you haven't conducted any scientific study nor do your references pertain to coffee. Your idea has been cited in many media as scientific and I feel this is misleading.

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    4. This comment has been removed by the author.

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    5. Do you know that this post is cited in the BCC article: "100 things we learned in 2013"? I wanna join Ryan and agoodkeensavage to say that your blog post became misquoted by the media. I am 100% sure your science communication efforts are genuine and you are interested in correctly inform people, but I am afraid this slipped off your fingers.

      I'm writing a list of the pseudoscience claims featured in that BBC article, and I am sorry to say that, since direct evidence of what you are claiming are missing in this post, I will have to add "best time to drink coffee" to the list.
      I'll be happy to hear more about this subject. I'm ready to revise my list as clearer evidence will come.

      Ultimatly, "striking correlations between the number of major disasters (Chernobyl, 3-mile island, and others) and cortisol levels" also sound a bit too much. I'll be happy to read the articles if you could post here the links.

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    6. I don't have the article my professor cited with a figure demonstrating the time of day of major disasters plotted onto the circadian rhythm of cortisol, but the incident at 3-mile island occurred at 4 AM, and the incident at Chernobyl occurred at 1:23 AM. Times at which, for the workers, cortisol levels would like be at their lowest blood concentrations.

      Cortisol levels are directly related to alertness: http://www.ncbi.nlm.nih.gov/pubmed/9851761

      Impairments or desynchrony of the circadian clock are directly related to human error/injuries of shift-workers (night-work): For a good review on this see the link below
      http://www.ncbi.nlm.nih.gov/pubmed/20051441

      Since cortisol levels are extremely low for these workers since they are working during the times of typical sleep periods, caffeine is often prescribed (along with drugs like modafinil) and are considered extremely effective for these workers.

      One example of an article where caffeine late morning was not as effective as caffeine in the afternoon in improving alertness and attention can be found here: http://www.ncbi.nlm.nih.gov/pubmed/2098674

      Also, the phenomenon of the cortisol awakening response suggests that it is not necessary to consume caffeine immediately upon awakening even for people who wake up before cortisol's acrophase. For a review on this subject see: http://www.ncbi.nlm.nih.gov/pubmed/18854200

      And, although articles prescribing caffeine to shift workers for example is effective, I did not say that late evening (for example) would be an ideal time to consume caffeine as (again although extremely effective) caffeine within at 6 hours of sleep will disrupt your sleep cycle: http://www.aasmnet.org/jcsm/ViewAbstract.aspx?pid=29198

      I cannot control how certain media sites have cited my article and/or misinterpreted what I said/misquoted what I said. Also, several websites have quoted my blog post saying that I research caffeine, which I do not. Whenever I have found those websites, I have corrected them. It is also clear in my post that neither I nor did Debono et al., 2009 work on caffeine as I was sure to cite their article appropriately in normal citation format (citing for the statement you said; "This is because cortisol production is strongly related to your level of alertness and it just so happens that cortisol peaks for your 24 hour rhythm between 8 and 9 AM on average (Debono et al., 2009).").

      If you are also questioning whether or not light can increase alertness, here is another example: http://www.ncbi.nlm.nih.gov/pubmed/24282477

      As far as your claim that this post is 'pseudoscientific,' I disagree. It cannot be pseudoscientific because I never claimed to have/nor am I misrepresenting the fact as to whether or not I conducted a study on the best time to consume coffee or caffeine; I did not. Another hallmark of pseudoscience is that is it not plausible (which many of the radio stations, news websites and people who have talked to me about this article agree that this post is), something that's pseudoscience is also not testable, and this certainly is testable. Further, none of the claims I made are vague (another hallmark of pseudoscience) and I was very careful to say things like, 'on average', when speaking about cortisol's acrophase. Regardless of different circadian schedules, the cortisol awakening response (and if you are on a regular sleep schedule and are not sleep deprived) would suggest that you would not need caffeine immediately upon waking. Not to mention that again, this is a blog post, any website that thought I was talking about primary data is simply unfamiliar with the publication process in science and does not realize that this blog is simply for science news/education/popular-science.

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  11. I heard a rumour that caffeine also occurs in TEA.
    Black Tea, Green tea etc **
    Presumably the theorem extends to TEA drinkers also...???
    ** and from various foods and drinks containing products derived from the kola nut. Other sources include yerba maté, guarana berries, guayusa, and the yaupon holly

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    1. Mike, I used coffee as my muse for this article but I am not a huge coffee person. I'm a soda junkie. This applies to caffeine in general.

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  12. Interesting article! I'm an early riser; I get up at 5am. How would you suggest I approach my morning brew(s)?

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  13. This comment has been removed by the author.

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  14. Great topic. So, how about in the evening?

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  15. Don't your cortisol level react to, if you eat breakfast or not? The timing of caffeine does not really matter if you fuck your cortisol level up with a meal of breakfast.
    Correct me if I'm wrong, I'm no scientist, just very interested in the subject.
    Got my knowledge from Dave Asprey.

    Sebastian

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  16. The time seems irrational. Why time? I'm already awake and up 7 hours by that time.
    Seems it would be more important and relevant as well as applicable to know how many hours after one has awakened and started their day. 03:00 as I do, 06:00, 07:00 or those who like to sleep really late 10:00 hours? What about the night shift? Those folks are awake from somewhere around 22:00 hours until 08:00 hrs the next day.
    This partly true story has been on nearly every news outlet this week, but is is pure nonsense if no one knows the time from when the people get awake before the best time to drink coffee.

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  17. Thanks for the insight into caffeine in relation to the stress hormone Cortisol. You have given me new ideas to think about in the relation of Cortisol in regards to the SCN along with other limbic system structures. I wonder if there is a relationship between caffeine usage of those affected with Post-Traumatic Stress Disorder and other Anxiety disorders in comparison to unaffected parts of the population.

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  18. How about everyone tries replacing coffee and fast food with exercise and put starbucks and mcdonalds out of business.

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  19. "Do you ever drink coffee and feel like it just didn't work". What do you mean "work"??? I drink coffee for the taste and the pleasure, just as I do with other beverages and foods I like, and also because it is a social act to have coffee together. Not for it to "work".
    This means I can drink coffee any time of day, when I feel like it or have a good occasion to. It is not a "dose" I take daily, like a drug. As for the notion that one can't have coffee in the afternoon, that is just a myth. I was raised in a family where my parents could say, towards 11 pm. "Shall we have a cup of coffee before we go to bed? It gives such a good sleep."
    Stop comparing coffee, this heavenly beverage and gift to mankind, to medicine!

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  20. Note to self: Add coffee to religion and politics.

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  21. It's nice that the best coffee can be found on almost every corner!
    -Jackie

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  22. Hi Steven! Great research! I've always wondered when the best time for a coffee was! I work for a radio station all the way over in New Zealand and we were wondering if we could do a quick pre-recorded interview with you? Be great to have a chat about it!

    My email is: Chrisgoodwin@hauraki.co.nz

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  23. Thanks for sharing good and helpful article with us. This is very helpful for me.
    Roasted coffee beans

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  24. Mary I add my case: I've found that if I drink just one coffee for three days in a row, my nervous system goes into stress.
    Maybe it's a personal intolerance (I've read somewhere that coffee may induce an allergic reaction) but it's evident that my body keeps the level of the substance for quite a long time, and I wouldn't blame caffeine in particular since caffeine free gives me the same effect.
    Btw, you wouldn't believe but I'm Italian.

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  26. Wow! This is very informative. It is indeed true. Too much consumption of a drug can cause the body to develop resistance to that drug. Such example is the body’s tendency to develop resistant to Mefenamic Acid after frequent use. Everything must be taken only when needed. This would be a good heads up to employers so that they can schedule their morning coffee breaks at the optimal hours.

    Catherine Anderson

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  27. I love this post. Good thing I always have a k cup around 10 AM. I noticed it helps me so much more than right at 9 AM.

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  30. Coffee is the most popular beverages entire the world because there are also health benefits of drinking coffee. I prefer to drink black coffee in the morning empty stomach which help to reduce fat.

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